Scientists in China and the US have synthesised and characterised the first all-boron fullerene-like structure, named borospherene.

Boron cages have been hypothesised for some time and their existence has been supported by computation but they have never been realised until now. The description in Nature Chemistry describes how a laser vaporisation cluster source was fired at a 10B-enriched boron disc in the presence of an argon-helium gas mixture and the products were checked out by photoelectron spectroscopy.

The cage-like B40– structure has a characteristically simple spectrum, which had a large energy gap between the highest and lowest unoccupied molecular orbitals, giving it a highly stable structure. It consisted of 16 tetra- and 24-pentacoordinated B atoms in a structure similar to that of a Chinese red lantern. By comparison with calculations, a structural isomer with a quasi-planar structure was also characterised.

As well as being a synthetic exercise, further calculations revealed that the borofullerene structures could be modified by metal atoms such as Ca, Y or La to produce compounds that might be useful for hydrogen storage. All B atoms are positioned at the edge of a hexagonal of heptagonal hole, which would make them available for the adsorption of hydrogen.